CA2061403C - Process for producing multilayer molded article - Google Patents
Process for producing multilayer molded article Download PDFInfo
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- CA2061403C CA2061403C CA002061403A CA2061403A CA2061403C CA 2061403 C CA2061403 C CA 2061403C CA 002061403 A CA002061403 A CA 002061403A CA 2061403 A CA2061403 A CA 2061403A CA 2061403 C CA2061403 C CA 2061403C
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- Prior art keywords
- skin material
- molds
- pins
- molded article
- multilayer molded
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14065—Positioning or centering articles in the mould
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/1418—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles the inserts being deformed or preformed, e.g. by the injection pressure
- B29C45/14262—Clamping or tensioning means for the insert
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/17—Component parts, details or accessories; Auxiliary operations
- B29C45/46—Means for plasticising or homogenising the moulding material or forcing it into the mould
- B29C45/56—Means for plasticising or homogenising the moulding material or forcing it into the mould using mould parts movable during or after injection, e.g. injection-compression moulding
- B29C45/561—Injection-compression moulding
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14065—Positioning or centering articles in the mould
- B29C2045/14147—Positioning or centering articles in the mould using pins or needles penetrating through the insert
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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Casting Or Compression Moulding Of Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
A multilayer molded article has a core layer and a skin material laminated on the core layer. The article is produced by positioning a skin material between a pair of upper and lower molds, supplying a thermoplastic resin melt between the skin material and one of the molds, closing the molds to press and form the resin melt while holding the edges of the skin material with pins on a frame that extends along an outer peripheral wall of one of the molds. The molds are finally cooled and the multilayer molded article removed therefrom.
Description
_ 1 _ 2061403 PROCESS FOR PRODUCING MULTILAYER MOLDED ARTICLE
The present invention relates to a process for producing a multilayer molded article that comprises a core layer of a thermoplastic resin and a skin material laminated on the core layer.
A large number of plastic molded articles are used in many fields, including the automobile and domestic electric appliance fields, because of their low costs, free moldability and light weight. However, they have some drawbacks, such as a poor appearance and a cool feel, and they tend to be easily flawed. It is highly desirable to impart decoration and a soft feel to such plastic molded articles. Hitherto, many attempts have been made to provide a compound that satisfies this desire, but it has been difficult to produce a molded resin article having improved surface properties while maintaining free moldability and strength from a single material, and at present multilayer molded articles each comprising a combination of a plurality of materials that have different functions are generally used.
Many processes are known for the production of a multilayer molded article. For example, Japanese Patent Kokai Publication No. 13859/1976 discloses a process comprising preforming a skin material by, for example, thermoforming, placing the preformed skin material in a mold, supplying a core resin melt and then integrating these elements together.
This process requires many molding steps and pieces of apparatus. In addition, since each piece of apparatus and each molding method has its own technical problems, much operation, maintenance and expense are necessary to produce the final product.
As disclosed in Japanese Patent Publication No. 19132/1975, another process molds a multilayer molded article using a single mold having a vacuum molding function and core resin supplying means. But, this process is no better than the above process.
_ 2 _ 206140 To overcome the drawbacks of the two above processes, Japanese Patent Kokai Publication No. 63461/1978 discloses a process comprising placing an unpreformed skin material in a mold and then integrating the skin material and the core resin. Although this process is economical, the tension of the skin material is controlled only in one direction and not in other directions. As a result, the skin material tends to be wrinkled, so that this process can produce only an article of simple shape; not a deep draw molded article.
As proposed in Japanese Patent Publication No. 24807/1988, a multilayer molded article can be produced by clamping the edges of a piece of skin material between a female mold and a skin material-fixing frame, preformed the skin material, supplying a melt of a thermoplastic resin as the core material and then molding the resin. This process is not necessarily satisfactory for molding a large size article, in particular, one having a complicated shape.
One object of the present invention is to provide a process for producing a multilayer molded article, which process solves the problems of the conventional molding processes.
Another object of the present invention is to provide a process for producing a multilayer molded article having a good appearance without wrinkles or breakage of the skin material.
A further object of the present invention is to provide a process for producing a multilayer molded article, which process can simplify the production steps and produce the article economically.
According to the present invention, there is provided a process for producing a multilayer molded article comprising a core layer and a skin material laminated thereon, which process comprises the steps of:
providing a skin material between a pair of upper and lower molds, supplying a thermoplastic resin melt between said skin material and one of the molds, .,.
closing the molds to press and form the resin melt while holding the edges of said skin material with pins provided on a skin material-fixing frame that moves along an outer peripheral wall of one of the upper and lower molds and cutting the skin material locally at one or more of the pins to all~a the skin material to slide into the melds, and cooling the molds and rgmying the multilayer molded article from the melds.
In the drawings:
Figs. 1A and 1B are vertical cross sectional views of an example of molds used in a molding process according to an embodiment of the present invention;
Fig. 2 is a plan view of an example of a skin material-fixing frame with pins;
Fig. 3 is a perspective view of an example of a multilayer molded article produced by the above process;
Figs. 4A and 4B are vertical cross sectional views of another example of molds used in a molding process according to an embodiment of the present invention: and Fig. 5 (with Fig. 2) is a plan view of another example of a skin material-fixing frame.
Examples of a skin material to be used in a process of the present invention are woven or nonwoven fabric, a sheet or film of a thermoplastic resin (e. g. polyolefin, polyvinyl chloride, polyamide, etc.) and a thermoplastic elastomer (e.g. polyolefin type, polyester type, polyurethane type and polyvinyl chloride type thermoplastic elastomers) or the like.
These skin materials can be used independently, or in the form of a laminate of two or more of them. Further, the skin material can be lined with a foam sheet of polypropylene, polyethylene or polyurethane to impart a soft feel, or with a fabric or a sheet to protect the skin material from the heat of the thermoplastic resin melt, or to enhance the adhesion between the skin material and the core layer. Before being placed in the mold, the skin material may be preheated in order to adjust its tensile stress or elongation.
20b1403 As a thermoplastic resin used as the core layer material, any one of conventional thermoplastic resins that are used in compression molding, injection molding and extrusion molding can be used. Specific examples are thermoplastic resins (e. g. polypropylene, polyethylene, polystyrene, acrylonitrile-styrene-butadiene copolymer, polyamide, etc.) and thermo-plastic elastomers (e. g. ethylene-propylene block copolymer, styrene-butadiene block copolymer, etc.).
The thermoplastic resin may contain at least one conventional additive, for example, a filler such as an inorganic filler and glass fiber: a pigment: a lubricant; and an antistatic agent.
In the process of the present invention, a skin material-fixing frame with pins is used, which frame moves along the peripheral wall of one of the upper and lower molds. The pins can be located on an upper or a lower surface of the frame.
Preferably, each pin has a diameter of 3 to 6 mm, and protrudes for a length of about 20 mm from the surface of the frame.
The skin material-fixing frame is provided around the upper or lower mold, using expansion-contraction means such as a spring, an air cylinder, a hydraulic cylinder, etc. This frame may be permanently or detachably connected to the expansion-contraction means. When the frame is a detachable one, a plurality of frames are used and, while one of them is used in the molding process, skin material is set on one of the other frames and immediately used in the next molding process, whereby the molding cycle is shortened.
The skin material may be set on the pins by piercing the skin material with the pins or by making small holes in the skin material at positions corresponding to the positions of the pins and passing each pin through a corresponding hole.
The thermoplastic resin is then press molded by closing the molds while holding the edges of the skin material with the pins to produce a multilayer molded article having the laminated skin material thereon. Since tension is applied on the skin material so that it is cut by the pin from the pin position towards the center of the mold, the amount of the skin material that slides in the mold can be controlled by adjusting the diameter of each pin and the density of the pins, so as to partly adjust the holding force on the skin material. If all the pins have the same diameter, at a part where the pin density is large, the holding force of the skin material is large so that the slid-in amount of the skin material is small, while at a part where the pin density is small, the holding force of the skin material is small so that the slid-in amount of the skin material is large.
For example, if the skin material is laminated all over a surface of a box-shape article, a part of the skin material at each corner tends to be wrinkled. To prevent such wrinkling at the corners, a larger number of the pins is provided at such parts to increase the holding force. If the skin material is found to be torn or stretched excessively, it is mounted on the pins in a slightly slack state.
A pin with a large diameter provides a larger holding force than a pin with a small diameter, so that the slid-in amount of the skin material is reduced. Therefore, this slid-in amount can also be adjusted by changing the pin diameter.
Since a part of the skin material held on the pin tends to be cut in the direction towards the center of the mold, each pin is preferably positioned outwardly from the mold part corresponding to the article edge by at least 10 mm. For workability when setting the skin material on the frame and the durability of the pins, the diameter of each pin is preferably from 3 mm to 6 mm.
The melt of the thermoplastic resin of the core layer can be supplied from a resin supplying apparatus provided outside the molds or through a conduit in either of the upper and lower molds. Preferably, the mold closing rate is adjusted at 30 mm/sec. or less, and the thermoplastic resin melt is supplied when a clearance between the upper and lower molds is from (C + 5) mm to (C + 100) mm, wherein C is the clearance when the molding is finished. After the resin melt is supplied, the molds are further closed to the clearance of C mm, pressed for a predetermined time and cooled to obtain the desired multilayer molded article.
The present invention will be illustrated by the following Examples.
Example 1 To a pressing machine having a clamping force of 400 tons, a pair of molds 1, 2 for forming the article of Fig. 3 were attached. The molds and the skin material-fixing frame 4 were arranged as shown in Fig. 1. As shown in Fig. 2, the frame 4 had, on its upper surface, pins 5 each having a diameter of 5 mm and a length of 20 mm at a distance of 230 mm on each side and at a distance of 50 mm on each corner.
As the skin material 7, there was used an embossed polyvinyl chloride sheet lined with an expandable fabric having a total thickness of 0.7 mm (manufactured by Kyowa Leather Co., Ltd.). As the thermoplastic resin, there was used a polypropylene containing 15% of talc (Sumitomo Noblen BPZ 5077 manufactured by Sumitomo Chemical Co., Ltd.; Melt flow index of 40 g/10 min.). The upper and lower molds were maintained at 50°C and 60°C, respectively.
The skin material 7 was held on the frame 4 by piercing it with the pins 5. The lower mold 2 was elevated to contact the frame 4 and the upper mold 1 through the skin material 7.
When the lower mold was further elevated, expansion means 6 was contracted by the lifting force of the lower mold 2, so that the outer side wall of the upper mold 1 and the inner side wall of the lower mold 2 mated with each other through the skin material 7 to form a closed cavity.
The lower mold 2 was further elevated. When the cavity clearance reached 50 mm, the lifting speed of the lower mold was decreased to 7 mm/min. and thermoplastic resin 8, which had been heated and molten at 220°C, was supplied between the skin material 7 and the upper mold 1 through a conduit 3 in the upper mold (Fig. 1A). The resin supply was stopped when the clearance reached 20 mm.
When the lower mold 2 was further elevated, the molten resin was compressed and flowed to press the skin material 7 against the lower mold wall, while expanding the skin material 7 to fill the mold cavity (Fig. 1B).
When the clearance had reached 3.1 mm, the frame 4 contacted a horizontal part of the upper mold 1, whereupon the elevation of the lower mold 2 was stopped. In this state, the molds were pressed together and cooled for 40 seconds. Then the lower mold 2 was lowered, and the molded article was removed. The article consisted of a core layer having a thickness of 2.5 mm covered with an embossed skin material having no wrinkles or breakage.
Example 2 To a pressing machine having a clamping force of 400 tons, a pair of molds for forming the article of Fig. 3 were attached. The molds 1, 2 and the skin material-fixing frame 4 were arranged as shown in Fig. 4. As shown in Fig. 5, the frame 4 had, on its upper surface, pins 5 each having a diameter of 5 mm and a length of 20 mm at a distance of 230 mm on each side and at a distance of 50 mm at each corner. At the center of each side, a bar-passing hole 11 was formed.
As the skin material 7, there was used an embossed polyvinyl chloride sheet having a thickness of 0.5 mm lined with a polypropylene foam sheet having a thickness of 3.0 mm (manufactured by Toray, an expansion ratio of 15). As the thermoplastic resin 8, there was used a polypropylene containing 15~ of talc (Sumitomo Noblen BPZ 5077 manufactured by Sumitomo Chemical Co., Ltd.; Melt flow index of 40 g/10 min.). The upper and lower molds were maintained at 20°C and 30°C, respectively.
The skin material 7 was held on the frame 4 by piercing it with the pins 5. The upper mold 1 was lowered to contact the frame 4 and the upper mold 1 through the skin material 7.
When the upper mold was further lowered, expansion means 10 was contracted by the downward force of the upper mold, so that the outer side wall of the upper mold 1 and the inner side wall of the lower mold 2 mated with each other through the skin material 7 to form a closed cavity.
_ ~U61403 The upper mold 1 was further lowered. When the cavity clearance reached 50 mm, the lowering speed of the upper mold was decreased to 7 mm/min. and the thermoplastic resin 8, which had been heated and molten at 190°C, was supplied between the skin material 7 and the lower mold 2 through a resin conduit 3 in the lower mold (Fig. 4A). The resin supply was stopped when the clearance had reached 20 mm.
When the upper mold 1 was further lowered, the molten resin was compressed and flowed to press the skin material 7 against the upper mold wall and to expand the skin material 7 to fill the mold cavity (Fig. 4B).
When the clearance had reached 2.7 mm, the frame 4 contacted a horizontal part of the lower mold 2, whereupon the lowering of the lower mold 2 was stopped. In this state, the molds were pressed together and cooled for 40 seconds. The upper mold 1 was then lifted and the molded article removed.
This article consisted of a core layer having a thickness of 2.0 mm covered with an embossed skin material having no wrinkles or breakage.
A
The present invention relates to a process for producing a multilayer molded article that comprises a core layer of a thermoplastic resin and a skin material laminated on the core layer.
A large number of plastic molded articles are used in many fields, including the automobile and domestic electric appliance fields, because of their low costs, free moldability and light weight. However, they have some drawbacks, such as a poor appearance and a cool feel, and they tend to be easily flawed. It is highly desirable to impart decoration and a soft feel to such plastic molded articles. Hitherto, many attempts have been made to provide a compound that satisfies this desire, but it has been difficult to produce a molded resin article having improved surface properties while maintaining free moldability and strength from a single material, and at present multilayer molded articles each comprising a combination of a plurality of materials that have different functions are generally used.
Many processes are known for the production of a multilayer molded article. For example, Japanese Patent Kokai Publication No. 13859/1976 discloses a process comprising preforming a skin material by, for example, thermoforming, placing the preformed skin material in a mold, supplying a core resin melt and then integrating these elements together.
This process requires many molding steps and pieces of apparatus. In addition, since each piece of apparatus and each molding method has its own technical problems, much operation, maintenance and expense are necessary to produce the final product.
As disclosed in Japanese Patent Publication No. 19132/1975, another process molds a multilayer molded article using a single mold having a vacuum molding function and core resin supplying means. But, this process is no better than the above process.
_ 2 _ 206140 To overcome the drawbacks of the two above processes, Japanese Patent Kokai Publication No. 63461/1978 discloses a process comprising placing an unpreformed skin material in a mold and then integrating the skin material and the core resin. Although this process is economical, the tension of the skin material is controlled only in one direction and not in other directions. As a result, the skin material tends to be wrinkled, so that this process can produce only an article of simple shape; not a deep draw molded article.
As proposed in Japanese Patent Publication No. 24807/1988, a multilayer molded article can be produced by clamping the edges of a piece of skin material between a female mold and a skin material-fixing frame, preformed the skin material, supplying a melt of a thermoplastic resin as the core material and then molding the resin. This process is not necessarily satisfactory for molding a large size article, in particular, one having a complicated shape.
One object of the present invention is to provide a process for producing a multilayer molded article, which process solves the problems of the conventional molding processes.
Another object of the present invention is to provide a process for producing a multilayer molded article having a good appearance without wrinkles or breakage of the skin material.
A further object of the present invention is to provide a process for producing a multilayer molded article, which process can simplify the production steps and produce the article economically.
According to the present invention, there is provided a process for producing a multilayer molded article comprising a core layer and a skin material laminated thereon, which process comprises the steps of:
providing a skin material between a pair of upper and lower molds, supplying a thermoplastic resin melt between said skin material and one of the molds, .,.
closing the molds to press and form the resin melt while holding the edges of said skin material with pins provided on a skin material-fixing frame that moves along an outer peripheral wall of one of the upper and lower molds and cutting the skin material locally at one or more of the pins to all~a the skin material to slide into the melds, and cooling the molds and rgmying the multilayer molded article from the melds.
In the drawings:
Figs. 1A and 1B are vertical cross sectional views of an example of molds used in a molding process according to an embodiment of the present invention;
Fig. 2 is a plan view of an example of a skin material-fixing frame with pins;
Fig. 3 is a perspective view of an example of a multilayer molded article produced by the above process;
Figs. 4A and 4B are vertical cross sectional views of another example of molds used in a molding process according to an embodiment of the present invention: and Fig. 5 (with Fig. 2) is a plan view of another example of a skin material-fixing frame.
Examples of a skin material to be used in a process of the present invention are woven or nonwoven fabric, a sheet or film of a thermoplastic resin (e. g. polyolefin, polyvinyl chloride, polyamide, etc.) and a thermoplastic elastomer (e.g. polyolefin type, polyester type, polyurethane type and polyvinyl chloride type thermoplastic elastomers) or the like.
These skin materials can be used independently, or in the form of a laminate of two or more of them. Further, the skin material can be lined with a foam sheet of polypropylene, polyethylene or polyurethane to impart a soft feel, or with a fabric or a sheet to protect the skin material from the heat of the thermoplastic resin melt, or to enhance the adhesion between the skin material and the core layer. Before being placed in the mold, the skin material may be preheated in order to adjust its tensile stress or elongation.
20b1403 As a thermoplastic resin used as the core layer material, any one of conventional thermoplastic resins that are used in compression molding, injection molding and extrusion molding can be used. Specific examples are thermoplastic resins (e. g. polypropylene, polyethylene, polystyrene, acrylonitrile-styrene-butadiene copolymer, polyamide, etc.) and thermo-plastic elastomers (e. g. ethylene-propylene block copolymer, styrene-butadiene block copolymer, etc.).
The thermoplastic resin may contain at least one conventional additive, for example, a filler such as an inorganic filler and glass fiber: a pigment: a lubricant; and an antistatic agent.
In the process of the present invention, a skin material-fixing frame with pins is used, which frame moves along the peripheral wall of one of the upper and lower molds. The pins can be located on an upper or a lower surface of the frame.
Preferably, each pin has a diameter of 3 to 6 mm, and protrudes for a length of about 20 mm from the surface of the frame.
The skin material-fixing frame is provided around the upper or lower mold, using expansion-contraction means such as a spring, an air cylinder, a hydraulic cylinder, etc. This frame may be permanently or detachably connected to the expansion-contraction means. When the frame is a detachable one, a plurality of frames are used and, while one of them is used in the molding process, skin material is set on one of the other frames and immediately used in the next molding process, whereby the molding cycle is shortened.
The skin material may be set on the pins by piercing the skin material with the pins or by making small holes in the skin material at positions corresponding to the positions of the pins and passing each pin through a corresponding hole.
The thermoplastic resin is then press molded by closing the molds while holding the edges of the skin material with the pins to produce a multilayer molded article having the laminated skin material thereon. Since tension is applied on the skin material so that it is cut by the pin from the pin position towards the center of the mold, the amount of the skin material that slides in the mold can be controlled by adjusting the diameter of each pin and the density of the pins, so as to partly adjust the holding force on the skin material. If all the pins have the same diameter, at a part where the pin density is large, the holding force of the skin material is large so that the slid-in amount of the skin material is small, while at a part where the pin density is small, the holding force of the skin material is small so that the slid-in amount of the skin material is large.
For example, if the skin material is laminated all over a surface of a box-shape article, a part of the skin material at each corner tends to be wrinkled. To prevent such wrinkling at the corners, a larger number of the pins is provided at such parts to increase the holding force. If the skin material is found to be torn or stretched excessively, it is mounted on the pins in a slightly slack state.
A pin with a large diameter provides a larger holding force than a pin with a small diameter, so that the slid-in amount of the skin material is reduced. Therefore, this slid-in amount can also be adjusted by changing the pin diameter.
Since a part of the skin material held on the pin tends to be cut in the direction towards the center of the mold, each pin is preferably positioned outwardly from the mold part corresponding to the article edge by at least 10 mm. For workability when setting the skin material on the frame and the durability of the pins, the diameter of each pin is preferably from 3 mm to 6 mm.
The melt of the thermoplastic resin of the core layer can be supplied from a resin supplying apparatus provided outside the molds or through a conduit in either of the upper and lower molds. Preferably, the mold closing rate is adjusted at 30 mm/sec. or less, and the thermoplastic resin melt is supplied when a clearance between the upper and lower molds is from (C + 5) mm to (C + 100) mm, wherein C is the clearance when the molding is finished. After the resin melt is supplied, the molds are further closed to the clearance of C mm, pressed for a predetermined time and cooled to obtain the desired multilayer molded article.
The present invention will be illustrated by the following Examples.
Example 1 To a pressing machine having a clamping force of 400 tons, a pair of molds 1, 2 for forming the article of Fig. 3 were attached. The molds and the skin material-fixing frame 4 were arranged as shown in Fig. 1. As shown in Fig. 2, the frame 4 had, on its upper surface, pins 5 each having a diameter of 5 mm and a length of 20 mm at a distance of 230 mm on each side and at a distance of 50 mm on each corner.
As the skin material 7, there was used an embossed polyvinyl chloride sheet lined with an expandable fabric having a total thickness of 0.7 mm (manufactured by Kyowa Leather Co., Ltd.). As the thermoplastic resin, there was used a polypropylene containing 15% of talc (Sumitomo Noblen BPZ 5077 manufactured by Sumitomo Chemical Co., Ltd.; Melt flow index of 40 g/10 min.). The upper and lower molds were maintained at 50°C and 60°C, respectively.
The skin material 7 was held on the frame 4 by piercing it with the pins 5. The lower mold 2 was elevated to contact the frame 4 and the upper mold 1 through the skin material 7.
When the lower mold was further elevated, expansion means 6 was contracted by the lifting force of the lower mold 2, so that the outer side wall of the upper mold 1 and the inner side wall of the lower mold 2 mated with each other through the skin material 7 to form a closed cavity.
The lower mold 2 was further elevated. When the cavity clearance reached 50 mm, the lifting speed of the lower mold was decreased to 7 mm/min. and thermoplastic resin 8, which had been heated and molten at 220°C, was supplied between the skin material 7 and the upper mold 1 through a conduit 3 in the upper mold (Fig. 1A). The resin supply was stopped when the clearance reached 20 mm.
When the lower mold 2 was further elevated, the molten resin was compressed and flowed to press the skin material 7 against the lower mold wall, while expanding the skin material 7 to fill the mold cavity (Fig. 1B).
When the clearance had reached 3.1 mm, the frame 4 contacted a horizontal part of the upper mold 1, whereupon the elevation of the lower mold 2 was stopped. In this state, the molds were pressed together and cooled for 40 seconds. Then the lower mold 2 was lowered, and the molded article was removed. The article consisted of a core layer having a thickness of 2.5 mm covered with an embossed skin material having no wrinkles or breakage.
Example 2 To a pressing machine having a clamping force of 400 tons, a pair of molds for forming the article of Fig. 3 were attached. The molds 1, 2 and the skin material-fixing frame 4 were arranged as shown in Fig. 4. As shown in Fig. 5, the frame 4 had, on its upper surface, pins 5 each having a diameter of 5 mm and a length of 20 mm at a distance of 230 mm on each side and at a distance of 50 mm at each corner. At the center of each side, a bar-passing hole 11 was formed.
As the skin material 7, there was used an embossed polyvinyl chloride sheet having a thickness of 0.5 mm lined with a polypropylene foam sheet having a thickness of 3.0 mm (manufactured by Toray, an expansion ratio of 15). As the thermoplastic resin 8, there was used a polypropylene containing 15~ of talc (Sumitomo Noblen BPZ 5077 manufactured by Sumitomo Chemical Co., Ltd.; Melt flow index of 40 g/10 min.). The upper and lower molds were maintained at 20°C and 30°C, respectively.
The skin material 7 was held on the frame 4 by piercing it with the pins 5. The upper mold 1 was lowered to contact the frame 4 and the upper mold 1 through the skin material 7.
When the upper mold was further lowered, expansion means 10 was contracted by the downward force of the upper mold, so that the outer side wall of the upper mold 1 and the inner side wall of the lower mold 2 mated with each other through the skin material 7 to form a closed cavity.
_ ~U61403 The upper mold 1 was further lowered. When the cavity clearance reached 50 mm, the lowering speed of the upper mold was decreased to 7 mm/min. and the thermoplastic resin 8, which had been heated and molten at 190°C, was supplied between the skin material 7 and the lower mold 2 through a resin conduit 3 in the lower mold (Fig. 4A). The resin supply was stopped when the clearance had reached 20 mm.
When the upper mold 1 was further lowered, the molten resin was compressed and flowed to press the skin material 7 against the upper mold wall and to expand the skin material 7 to fill the mold cavity (Fig. 4B).
When the clearance had reached 2.7 mm, the frame 4 contacted a horizontal part of the lower mold 2, whereupon the lowering of the lower mold 2 was stopped. In this state, the molds were pressed together and cooled for 40 seconds. The upper mold 1 was then lifted and the molded article removed.
This article consisted of a core layer having a thickness of 2.0 mm covered with an embossed skin material having no wrinkles or breakage.
A
Claims (5)
1. A process for producing a multilayer molded article comprising a core layer and a skin material laminated thereon, which process comprises the steps of:
providing a skin material between a pair of upper and lower molds, supplying a thermoplastic resin melt between said skin material and one of said molds, closing the molds to press and form said resin melt while holding edges of said skin material with pins provided on a skin material-fixing frame that moves along an outer peripheral wall of one of said upper and lower molds and cutting the skin material locally at one or more of the pins to allow the skin material to slide into the molds, and cooling the molds and removing the multilayer molded article from the molds.
providing a skin material between a pair of upper and lower molds, supplying a thermoplastic resin melt between said skin material and one of said molds, closing the molds to press and form said resin melt while holding edges of said skin material with pins provided on a skin material-fixing frame that moves along an outer peripheral wall of one of said upper and lower molds and cutting the skin material locally at one or more of the pins to allow the skin material to slide into the molds, and cooling the molds and removing the multilayer molded article from the molds.
2. The process according to claim 1, wherein each of said pins has a diameter of 3 to 6 mm and protrudes for a length of about 20 mm from a surface of said frame.
3. The process according to claim 1, wherein said skin material has holes at positions corresponding to positions of said pins, said pins passing through respective holes to set the skin material on the frame.
4. The process according to claim 1, wherein each of said pins is positioned outwardly from a mold part corresponding to the article edge by at least 10 mm.
5. A multilayer molded article produced by a process as claimed in claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2352891 | 1991-02-18 | ||
| JP23528/1991 | 1991-02-18 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2061403A1 CA2061403A1 (en) | 1992-08-19 |
| CA2061403C true CA2061403C (en) | 2004-02-17 |
Family
ID=12112951
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002061403A Expired - Lifetime CA2061403C (en) | 1991-02-18 | 1992-02-18 | Process for producing multilayer molded article |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US6183680B1 (en) |
| EP (1) | EP0500033B1 (en) |
| KR (1) | KR100189386B1 (en) |
| CA (1) | CA2061403C (en) |
| DE (1) | DE69210646T2 (en) |
| ES (1) | ES2090379T3 (en) |
| TW (1) | TW201285B (en) |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2695859B1 (en) * | 1992-09-22 | 1994-11-18 | Reydel J | Method for manufacturing a multilayer object by molding, object obtained and application to the manufacture of dashboards and / or trim elements of a vehicle body. |
| US6132669A (en) * | 1997-08-14 | 2000-10-17 | The Elizabeth And Sandor Valyi Foundation, Inc. | Process for preparing a molded article |
| JP4461518B2 (en) * | 1999-08-27 | 2010-05-12 | 住友化学株式会社 | Mold for manufacturing thermoplastic resin molded body and method for manufacturing thermoplastic resin molded body |
| FR2804057B1 (en) * | 2000-01-24 | 2002-09-20 | Plastic Omnium Cie | MOBILE JOINT PLAN MOLD FOR PRODUCING A PLASTIC PART AND A METHOD USING SUCH A MOLD |
| US20080265458A1 (en) * | 2007-04-24 | 2008-10-30 | Keith Hershner | Method for forming an over-molded product |
| CN101340784A (en) * | 2007-07-04 | 2009-01-07 | 深圳富泰宏精密工业有限公司 | Casing of electronic apparatus and manufacturing method thereof |
| CN101439572B (en) * | 2007-11-23 | 2011-11-16 | 康准电子科技（昆山）有限公司 | Molding device of in-mold decoration |
| CN101466209B (en) * | 2007-12-20 | 2012-03-14 | 深圳富泰宏精密工业有限公司 | Case |
| JP2011207022A (en) * | 2010-03-30 | 2011-10-20 | Nec Personal Products Co Ltd | Injection molding device, injection molding method and housing |
| FR2980130B1 (en) * | 2011-09-19 | 2013-10-11 | Visteon Global Tech Inc | SYSTEM FOR MANUFACTURING PARTS BY THERMOFORMABLE FILM TRANSFER ON AN OVERMOLDING DEVICE |
| CN111391216A (en) * | 2020-03-19 | 2020-07-10 | 福建省闽清双棱竹业有限公司 | Hot press for bamboo-plastic composite board and hot pressing process |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE833118C (en) * | 1950-12-31 | 1952-03-03 | Otto Zollfrank | Process for the production of molded articles made of thermoplastic materials with a similar film cover |
| DE1282294B (en) * | 1965-05-17 | 1968-11-07 | Desma Werke Gmbh | Process for the production of footbed soles from expandable material and injection mold to carry out the process |
| DE2548318A1 (en) * | 1975-10-29 | 1977-05-05 | Theysohn Friedrich Fa | METHOD AND DEVICE FOR COATING FILM MATERIAL |
| NL178400C (en) * | 1976-09-13 | Ici Ltd | DEVICE FOR FORMING AND SUBSEQUENTLY INJECTION MOLDING OF PLASTIC ON A MATERIAL PATH. | |
| US5223201A (en) * | 1984-12-07 | 1993-06-29 | Sumitomo Chemical Company | Method of manufacturing a laminated body |
| US5238640A (en) * | 1984-12-10 | 1993-08-24 | Sumitomo Chemical Co., Limited | Method of manufacturing a laminated body |
| CA1304552C (en) * | 1987-08-31 | 1992-07-07 | Syohei Masui | Process for producing a multilayer molded article |
| JPH01235613A (en) * | 1988-03-16 | 1989-09-20 | Sumitomo Chem Co Ltd | Manufacture of multi-layer molded item |
| US5009821A (en) * | 1989-02-23 | 1991-04-23 | Libbey-Owens-Ford Co. | Molding method for eliminating fiber readout |
| US5000903A (en) * | 1989-04-06 | 1991-03-19 | Libbey-Owens-Ford Co. | Method of molding plastic products having chemically bonded protective coatings |
-
1992
- 1992-02-15 TW TW081101076A patent/TW201285B/zh not_active IP Right Cessation
- 1992-02-17 DE DE69210646T patent/DE69210646T2/en not_active Expired - Lifetime
- 1992-02-17 EP EP92102657A patent/EP0500033B1/en not_active Expired - Lifetime
- 1992-02-17 ES ES92102657T patent/ES2090379T3/en not_active Expired - Lifetime
- 1992-02-18 CA CA002061403A patent/CA2061403C/en not_active Expired - Lifetime
- 1992-02-18 KR KR1019920002404A patent/KR100189386B1/en not_active IP Right Cessation
-
1995
- 1995-04-24 US US08/427,706 patent/US6183680B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| TW201285B (en) | 1993-03-01 |
| EP0500033B1 (en) | 1996-05-15 |
| US6183680B1 (en) | 2001-02-06 |
| DE69210646D1 (en) | 1996-06-20 |
| ES2090379T3 (en) | 1996-10-16 |
| DE69210646T2 (en) | 1996-09-26 |
| KR100189386B1 (en) | 1999-06-01 |
| CA2061403A1 (en) | 1992-08-19 |
| EP0500033A1 (en) | 1992-08-26 |
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| EEER | Examination request | ||
| MKEX | Expiry |